Butter is an edible emulsion spread consisting of a continuous fat phase and an aqueous phase which is dispersed as fine droplets in the fat phase. The fat phase consists of dairy fat, a 100% natural fat. Margarine too is a fat continuous emulsion, but margarine fat is not natural, but has been processed in order to give margarine properties desired for a spread. The fat phase of margarine and of similar fat continuous emulsion spreads is a mixture of a fat which is fully liquid (the oil part of the fat phase) and a fat which is solid at ambient temperature.
The solid fat, denoted as hardstock fat, serves to structure the fat phase and helps to stabilize the emulsion. For imparting to common margarine a semi-solid, plastic, spreadable consistency this stabilizing and structuring functionality plays an important role. The crystals of the solid fat form a network throughout the liquid oil resulting into a structured fat phase. The aqueous phase droplets are fixed within the spaces of the lattice of solid fat crystals. In this way coalescence of the droplets and separation of the heavier aqueous phase from the fat phase is prevented.
The technology of spread processing is well established. The type of fat and the ratio of liquid oil and solid fat are chosen such that after proper processing of the fat blend with an aqueous phase a plastic product with a suitable consistency and mouthfeel is obtained.
Vegetable oils are the usual source for preparing margarine fats. Vegetable fats are preferred over animal fats because their unsaturated fat composition enhances the spread's nutritional value. Besides that, vegetable fats are an abundant and relatively cheap resource. However, natural, non-processed vegetable fats which are suited as hardstock fat are rather rare.
Fractionation, hydrogenating and interesterification are the normally used treatments for turning liquid vegetable oils into suitable hardstock fats.
The present trend in food processing is to avoid processing, particularly chemical processing as much as possible and to opt for natural ingredients and natural processing. Natural means that the ingredients have a natural origin and after harvesting have been subjected to no other treatment than a refining or purification treatment and to no modification treatment whatsoever. This trend strongly appeals to present consumer appreciation. It also may contribute to the economy of the production process.
Generally, fats with a high content of HUH triglycerides show good structuring properties. H denotes a C16–C24 saturated fatty acid residue, such as palmitic acid (C16) or stearic acid (C18) and U denotes an unsaturated C18 fatty acid residue, such as oleic acid (C18:1) or linoleic acid (C18:2).
Cocoa butter is the only unprocessed fat which contains a high amount of HUH triglycerides and which has been used for margarine production. However, use of cocoa butter as hardstock fat for spread preparation entails serious disadvantages. Cocoa butter has a natural high content of palmitic acid. Palmitic acid has a well established negative effect on blood cholesterol level. Food containing a high palmitic acid content may contribute to increased incidence of cardiovascular disease. Further cocoa butter in its main application, chocolate manufacture, suffers from severe re-crystallisation phenomena, which is known as fat blooming. Similar defects are feared in spread preparation which would easily spoil the product's consistency.
Finally, cocoa butter is generally too expensive to serve as hardstock fat in margarine manufacture.
Shea fat, also having a high content of HUH triglycerides, ail needs to be fractionated before use, because it contains up to 10 wt. % of non-saponifiable matter. The stearin contains 73 wt. % of HUH where nearly all H are stearic acid residues and nearly all U are oleic acid residues. The high costs of fractionation are prohibitive for the commercial use of shea stearin in spread manufacture. Natural, non-processed hardstock fats with a high content of HUH in which H mainly is a stearic acid residue are still much sought ingredients for the manufacture of emulsion spreads with a wholly natural fat phase. The present invention satisfies the need of a natural non-processed hardstock fat with such triglyceride content.